1. Field of the Invention
The present invention relates to an engine having a charge motion control valve and induction system which will furnish charge air with high kinetic energy during most engine operating conditions.
2. Disclosure Information
In order to obtain maximum fuel economy with minimum tailpipe emissions, engine designers have striven for engines which tolerate both higher rates of exhaust gas recirculation (EGR) and lean of stoichiometric operation. One method for increasing an engine's tolerance to EGR while promoting highly stable combustion is to increase the combustion burn rate by increasing the kinetic energy or motion of the air charge entering the engine's cylinder. In this case, kinetic energy refers to translational, rotational, and vibrational motion of the air charge. In the past, designers have devised charge motion control valves comprising the familiar butterfly element, either used as a whole round plate situated within an intake runner, as shown in FIG. 8, or a plate having a cutout, as shown in FIGS. 9 and 10.
A problem with the valve plate shown in FIG. 8 is that flow passing over the upper and lower portions of the plate will recombine in trailing vortices, causing loss of downstream energy and velocity as air passes through the intake port and into the cylinder. In other words, the streamlines are not maintained, but are destroyed passing over the plate. FIG. 9 illustrates a plate having a cutout formed in one section thereof, and although the streamlines are maintained at one portion of the intake runner, there is a loss of energy caused by the sharp edged orifice cutout, which causes trailing vortices. FIG. 10, which is also prior art, illustrates a half plate which, once again, suffers from the problem that when the plate is in the fully opened position, air flowing above and below the plate combines into turbulent eddys which reduce flow through the port downstream of the plate. This is undesirable.
The foregoing defects of prior art systems are remedied by a charge motion control valve (CMCV) according to the present invention.